Voltage regulator



Aug. 24, 1937. F. w. GAY 2,090,671

VOLTAGE REGULATOR Filed Jan. 3, 1935 2 Sheets-Sheet l 5 E5 Q! INVENTORAug. 24, 1937.- F. w. GAY

VOLTAGE REGULATOR Filed Jan. 3. 1935 2 Sheets-Sheet 2 ZSI INVENTORgagerlfi'iz ATTbRNEY Patented Aug. 24, 1937 UNITED STATES PATENT OFFICEdclhima.

'Ihis invention relates to a novel alternating current voltageregulator, and particularly to a voltage regulator which may veryreadily be altered so as to have its voltage regulating range and amperecapacity increased or decreased in accordance with the requirements ofits associated feeder.

Voltage regulators are generally installed in substations having aplurality of feeders. When the substation is built these feedersgenerally number from four to six, increasing to twenty or more when thesubstation reaches its ultimate size. During the period of growth, asnew feeders are added, the load is continually redistributed among theold feeders and the effective length of each feeder is thus continuallychanged. It follows therefore, that the minimum required regulatingrange of the voltage regulating equipment connected to each feeder iscontinually changing during the growth of the substation. The maximumexpected load of each individual feeder is also continually beingchanged as the load is continually redistributed.

Voltage regulators as heretofore constructed have been, by design, offixed voltage range and definite ampere capacity. They are heavy,solidly connected to their circuits, and generally have associated withthem more or less complicated control circuits. If such heavy andexpensive units were continually changed to suit the varyingrequirementsof individual feeders, the expense of making each changewould be great and the accumulation of expense for repeated changeswouldbe exorbitant. Furthermore, so large a variety of sizes and amperecapacity regulators would be required that an excessive capitalinvestment would be tied up in idle regulators to meet a possible largedemand for a particular unit.

For the above reasons, users of voltage regulating equipment havegenerally determined in advance, both the maximum current each feeder ina given substation would ever be called upon to carry and the maximumvoltage boost required on any feeder. Regulators are then purchased,each satisfydng these maximum requirements. Such a standardizationpolicy may be justified where losses diminish to zero in proportion tothe square of the load carried. It is not Justified in the case of theregulator equipment where relatively large constant losses are presentand these constant losses vary, both with the current capacity and thevoltage regulating range. Furthermore, many regulators have an excessiveas well as substantially constant excitation demand.

A study of substations will show that in heavily loaded districts wheresubstations are .numerous and feeders short, the required buck and boostis about as follows. V of the total feeders will require from 5% buck to4% boost. V; of the total feeders will require from 5% buck ,to6% boost.y ofthetotalfeederswillrequire from 5% buck to 8% boost.

In lightly loaded districts where feeders are long, about V, of thetotal feeders will require from 5% buck to 6% boost. A of the totalfeeders will require from 5% buck to 10% boost. V; of the total feederswill require from 5% buck to over 10% boost. One or two feedersgenerally require up to 20% boost.

For feeders requiring an'excess of boost voltage over buck voltage, Ipropose to install in the regulator of the excess of boost voltage inthe form of permanent boost, so that an equal and minimum range of buckor boost will be required in the regulator.

It is to be noted that some manufacturers of regulators recommendcarrying a low feeder voltage to utilize the full buck of the regulatorand the setting of all transformers on the feeder on low taps tocompensate. Under these conditions the voltage on long feeders is pulleddown below what it should be, especially for maximum loads, and thefeeder current is correspondingly increased. Regulation increases withcurrent and the worst condition is made still worse.

It is the practice in many substations to install the substationequipment (0. C. B. and voltage regulators) of the maximum expectedsize, and to install feeder reactors of a size required by the feedercircuit and external to the regulator, so that during short circuitconditions the voltage regulator is subjected to both voltage andcurrent.

I propose to install a current limiting reactor in each regulator, soconnected that the regulator equipment cannot be simultaneouslysubjected to both maximum current and high voltage.

It is an object of my invention to provide a voltage regulating devicecomposed of a plurality of substantially identical voltage regulatingunits which are brought successively into a buck or boost relation withthe feeder circuit as required, each unit contributing a definitepredetermined buck or boost.

It is a further object of my invention to connect only so many units ina feeder circuit as may be needed to give the instant required buck orboost. The remaining units not needed but provided for in the design maybe short circuited,

disconnected, or absent. It is a further object of this invention tomake all units readily interchangeable so that new units may readily besubstituted of different ampere capacity. Or new units may besubstituted of greater or lesser buck or boost capacity. Or damagedunits may be promptly and cheaply replaced.

It is a further object of this invention to provide a regulating devicecomprising a plurality of regulating transformers and means tosuccessively change connections of the primaries of said regulatingtransformers from a short circuited condition to a regulating conditionor vice versa.

It is a further object of this invention to connect certain of the unitsin a voltage regulator in permanent boost relation for feeders requiringexcessive boost, whereby'the excessive and desired boost is obtainedwithout a corresponding and useless buck voltage.

It is a further object of thisinvention to permanently incorporate in avoltage regulator a reactor so connected as to protect the regulatoragainst the simultaneous occurrence of maximum current withsubstantially normal voltage.

It is a further object of this invention to switch capacitors into shuntacross a circuit simultaneously with the regulating transformers whereby.the power factor of the circuit may be continually adjusted to adesired or high value as an inductive load increases.

It is a'further object of this invention to switch a great number oftransformers into and out of an energizedcondition for regulatingpurposes: aid great number of transformers allowing each transformer tohave a large turn ratio and a correspondingly small current to beswitched. The invention is clearly illustrated in the accompanyingdrawings, in which:

Fig. 1 is a cross section of a voltage regulate comprising the presentinvention.

Fig. 2 is a diagrammatic representation of the regulator of Fig. 1.

Fig. 3 is a cross section in plan along line AA mg. 1.

Fig. 41s a cross section in plan along line BB Fig. 1. Fig. 5 is a crosssection in plan along line CC Fig. 1.

Fig. 6 shows an enlarged view of the switch operating mechanism of Fig.1.

In Fig. 1,20I represents a steel tank filled with oil to the level 215.Attached to the top or cover 202 is an angle ironrack 203 containing aplurality of racks 209, 203etc. To each of these racks is attached afast operating double throw switch commonly known to the trade as snapto over" type. These switches are numbered I50, I55, I30, I3, 23, 33,43, 53 and 53. The upper three switches, i. e. I50, I55 and I50 areoperated by rod 222 which engages the three switch handles 223. Red2221s actuated by a crank 05 connected to operating handle 22I by shaft2I9 iournaled in bearing 220. The lower six switches. i. e. I3, 23, 33,43, 53 and 63 are operated by the lug or finger 2l8 connected torevolving hub 2I5. Revolving hub 2I0 is moved up and down ver- 70tically by the nut 2I1 which is held against rotating by arm 224 andmoves up and down vertically onthreaded shaft 201. Threaded shaft 201 isheld in journals 205 and 205 and operated by hand wheel 208. Nut 2I1 isstopped In its 15 upward travel by step plate 225.

On angle iron rack 203 are located the additional shelves 2| 0, 2H, 2I2and 2I3 on which are mounted the various transformers, capacitors,lightning arrestors and reactors shown in Fig. 2.

Fig. 3 is a cross section in plan along line AA, Fig. 1 and shows thelocation of top "snap over" switch I50; the location of reactor I 40shunted across leads 6i and H1 (see Fig. 2); and the location of the twobanks of capacitors shunted across leads 5| and II8. (see Fig. 2).

Fig. 4 is a cross section in plan along line BB, Fig. 1 and showstransformers 40a and 401) with primaries shunted across leads 4| and 42,together with capacitors 58a and 58b and lightning arrestor 41 similarlyconnected. It also shows the location of the two similar bank oftransformers 50a and 50b and a and 6012 with their associated capacitorsand lightning arrestors.

Fig. 5 shows the location onshelf 2I3, Fig. 1 of the three transformersI20a, I20b, I200. It also shows the location of reactor I I0 (see Fig.2)

All transformers shown in the above figures have their secondariesconnected in series as shown in Fig. 2.

Fig. 6 shows an enlarged view of the operating nut 2I1 shown in Fig. 1.A key-way 230 is cut in the threaded shaft 201. Into this key-way'isfitted a woodrufl" key 23I secured in the revolving hub 216 so that hub216 and lug 218 revolve with shaft 201. With the nut in position shownin Fig. 6, swivel frame 232 is placed on top of hub 2I6 and swivel plate233 is screwed to hub 2I6. Hub 2| 5 with swivel frame 232 are now raiseduntil lug 2| 8 is in position to operate handle 223 of "snap over"switch I3 as shown. Swivel frame 232 is now attached to nut 2" bydrilling, tapping, and applying set screw 235. Arm 225 has a clevis atits outer end 238 (see Fig. 3). Arm 224 is welded to swivel frame 232 sothat swivel frame and nut 2I1 are held from revolving and travel up anddown on shaftv201 as shaft 201 is rotated back and forth. As shaft 201is rotated one revolution in the lowering direction, lug 2I8 makes onerevolution and travels down from the position A to dotted position B.Lug 2I3 was in juxtaposition with operatinghandle 223 of switch I3 andoperated switch I3 at the start of the first revolution. A secondrevolution brings lug 2I8 to position C. A third revolution brings lug2I8 to position D and fourth to position E. Any further revolution ofshaft 201 in this same direction will cause lug 218 to engage operatinghandle 223 of switch 23 and operate switch 23, etc.

The connections of the several parts of the device and their operationwill be obvious to one skilled in the art by consulting Fig. 2. Thefeeder circuit wires I15 and I16 are shown'connected to brushes I13 andI14 which contact slip rings HI and I12 of alternator I10. Lead I15connects to regulator terminal 111. This side of the cireuit passesthrough reactor I I0 and the scoop daries of the following transformersI0, 20, 30, 40a, 40b. 50a, 50b, 50a, 50b, I20c, I 2012, I200 and toterminal I18. Terminal I18 connects to feeder circuit wire I19. Wire I16constitutes the other side of the circuit and runs through to theutilization equipment. Shunt wire II3 connects wire I15 to shuntterminal I80.of the regulator.

The operation of this device is as follows.

Assume handle 22I (Fig. 1) is thrown so as to 7 close contacts I52 andI5I of switch I50, contacts I51 and I 55 of switch I55, and contacts I62and I6I of switch I50. Assume also that nut 21 1 is at the top of itstravel against stop plate 225. In

this position switches I3, 23, 33, 33, 53, and 63 are all thrown intothe upper position so as to close against contacts I4, 24, 34, 44, 54,and M respectively; thus short .circuiting primary windings IOP, 20P,30P, 40P, 50?, and 60P respectively.

It is thus seen that these buck and boost transformers iii to 60respectively are in a neutral condition. On the other hand, thetransformers Ia, I20b,- and I200 have their primaries connected inmultiple across the busses I21 and I 20. I21 is connected solidly to theterminal lead I13. I28 is connected to the opposite pole of the circuit,i. e. wire I16 by the Jumpers I20 and H3. 16 These three transformersare so connected that their secondaries are connected in series to con:tinuously boost the voltage of the source (alternator I10) a fixedamount, say three percent.

If now, handwheel 208 is turned to screw nut 20 2" downwards, lug 2I0turning with hub 2I5 immediately engages the handle 223 of snap switchI3 so that it flips over making connection between the hinge contact andthe stationary contact I6. This action takes place in the shortestpossible time by reason of the high speed action of snap switch I3. Theprimary of transformer I0 is now connected across the power circuit bythe following connections. Wire I16 through II3 to shunt terminal I80,jumper H2 to contact IIiI of switch I00, switch I60 to wire II3, jumperI I to primary IOP, primary IIIP through wire I2 to contact I5, contactI5 through switch I3 to contact I5, contact it through wire I I5 tocontact I51 of switch I55, through switch I55 to upper contact I56 andthen through wire II and reactor IIO to regulator terminal I11 whichconnects to wire I15.

If wheel 200 is continuously turned, hub 2i and lug 2 I 8 will continueto revolve together about shaft 201. v As it travels downward it willcontact successively the operating handles of snap switches 23, 33, 43,53, and 63 respectively, closing these switches in the downward position(see Fig.v 2). When these switches are in the downward position, theprimaries of all the transformers are in multiple across the powercircuit and transformers I0 to 60 respectively are connected to boostthe voltage across wires I13 and I18. For convenience in manufacturing,all the transformers are identical. It will therefore be seen that withnut 2I1 in its highest position against stop 225, the three transformersI200, I201), and I200 will each boost the voltage an equal amount, say1%, so that the total boost will initially 55 amount to 3%, i. e. thevoltage across the outgoing wires I16 and I19 will be approximately 3%higher than the voltage on the power source I15, I16. Now'as switch I3is snapped to its lower position, (see Fig. 2) by the downward travel of60 hub 2I6 and lug 2I8, primary IOP is thrown from a short circuited orno voltage position to a full voltage position across the power source,so that transformer I0 immediately adds 1% boost, making the totalvoltage on outgoing wires I16, I13 65 approximately 4% higher than thepower source I15, I16. In the samemanner, when switch 23 is snapped tothe lower position, transformer primary 20F is thrown from a shortcircuited condition to a full voltage condition, making the 70 totalboost 5%. And when switch 33 is snapped to the down position transformer30 is similarly energized and adds a 1% boost, making the total boost6%. When switch 43 is snapped down the primaries of both of thetransformers 30a and 75 b are thrown from a short circuited to a fullvoltage position, and since their secondaries are in series they eachadd a 1% boost, or a total of 2%, making the total boost of theregulator 8%. Similarly when switch I3 is snapped down transformer 50a.and 501) each add 1% boost making the total boost 10%, and when switch53 is snapped (Fig. 2) to the down position the total boost becomes 12%.

When each of these switches, as for instance I3 is thrown down, thecorresponding primary winding. as for instance IOP, is momentarily opencircuited, and since the inductively associated secondary MS may becarrying full load current, it follows that the associated primary I 0?must also carry substantially full load current or otherwise the currentin the primary would act as a magnetizing current and almost instantlybuild up an.excessively high voltage across the as I3 across IOP; etc.The function of each condenser is to carry the primary current duringthe switching period and it will be evident to one skilled in the artthat the shorter the switching time, the smaller will be the condenserrequired for this purpose. It is imporant to note that when thetransformer snap switches as for instance I3, 23, etc. are in the shortcircuiting position, i. e. up (Fig. 2) then the capacitors I8, 23, etc.are completely discharged arid are therefore prepared to absorb theprimary current; also when in the "across the line position, i. e..switch I3 down (Fig. 2) they. are fully charged at the instant ofmaximum voltage and current and are therefore in prime condition tofurnish the associated transformer primary with the necessary current.

It will of course be noted that when switchneutral position, thecondenser will be charged at the peak of the wave and if the feeder iscarrying a high power factor load the associated transformer primarywill charge it still further during the switching interval. Sinceoperation in the buck position is always at light load this conditionwill not materially increase the size of condenser required.

It will be noted that by using many transformer banks, each separatelyswitched, the current to be switched is kept at a very small value.

I have also shown across each transformer primary a lightning arresteras for instance I1 for transformer I0; 21 for transformer 20; 31 fortransformer 30, etc. This lightning arrester serves its usual functionto protect the transformer against high voltage during current surgeswhile switching.

It will be noted that switches I and I" as well as switch III are thrownin the up position for boost. Assuming again that nut 2" is in itstopmost position against the stop bracket 225 with switches I", I, and Ithrown in the down position (Fig. 2) a downward travel of nut 2I1 willagain operate switches I3 to 33, throwing them from the up position tothe down position (Fig. 2). This will again energize transformers I0 to00 respectivelybut in the reverse direction, i. e. each transformer asit is energized will add a 1% buck instead of boost. When switch I3 issnapped down energizing transformer III, the 3% boost produced by thetransformers I20a, l20b and i200 will be reduced to a 2% boost. Whenswitch v23 is snapped down energizing transformer 20 the boost will bereduced to 1% and when switch 03 is snapped down the boost will bereduced to zero, that is. the

voltage regulator willbe in the neutral position.

When switch 03 is snapped down and trans- 5 formers 50a and 40b areenergized, a 2% buck will be produced and when transformers 50a and 50band 50a and 50b are energized by snapping down switches 53 and 53 themaximum buck of 6% will be obtained. It will be noted that when switchesI50, I05 and I50 are thrown in the up position, a relatively largecapacitor bank I30, I30 (Fig. 2, see also Fig. 3) is connected directlyin multiple with the primaries of 00a. and 5017. 'Also that whenswitches I50, I55 and I50 are capacitor banks I30, I30 are disconnected,and a reactor I40 (see Fig. 2 and Fig. 3) is connected directly inmultiple with the primaries of 50a and 00b. It follows therefore, thatwhen switches I50, I55 and I50 are in the boost position, the capacitorbank I00, I30 is energized when the last boost position is reached, andwhen switches I50, I55 and I50 are thrown to the buck position a reactorI50 is energized at the instant the maximum buck position is reached, 1.e. when transformers 00a and 505 are energized.

It is to be understood that in practice the switch I50 may have aplurality of poles and the capacitor bank I00, I00 may be divided upinto a corresponding plurality of capacitors, each capacitor beingconnected across one of the transformer banks, as for instance I0, 20,00, 40, 50,50 no that capacitors are added in shunt across the feeder inaccordance with the amount of boost, and the amount of capacity in theseveral groups .may be altered to suit the requirements of the circuit.That is, a feeder carrying a motor load of low power factor with alighting peak of unity power factor will have the capacitors dis- 40tributed across the primaries of those transformers which are first cutin the circuit. On the other hand, a feeder carrying a steady load ofhigh power factor with an occasional motor load (as for instance a largepump of low power 45 factor) will have the capacitors distributed acrossthe primaries of the last transformer to be cut in circuit.

The reactor H0, Fig. 1 and Fig. 2, is connected in the circuit beforethe lead III is tapped oil. It .50 follows therefore that a shortcircuit on feeder wires I16, I19 will draw, a very large current whichwill be limited by the impedance of reactor IIO, so that there will be ahigh voltage across reactor IIO and a very low voltage across wires III55 and H2. It follows therefore, that if switches I 3, 23 to 60inclusive operate during the instant of the short circuit they will behandling a relatively high current, but a relatively low voltage. Asmany changes could be made in the above 60 construction and manyapparently widely different embodiments of this invention could be madethereof, it is intended that all mattercontained in the abovedescription or shown in the accompanying drawings shall be interpretedas illus- 65 trative and not in a limiting sense.

What is claimed is: 1. A voltage regulator provided-with racks, aplurality of substantially identical and interchangeable voltageregulating units mounted on 70 said racks, each of said units consistingof a transformer means and a switch connected to said transformer meansand arranged to throw its connected transformer means into and out ofregulating condition, whereby units may be added in sequence to increasethe regulating range thrown down, that is in the buck positionnthe.

of said regulator and extracted in the reverse sequence to diminish saleregulating range.

2. A voltage regulator tank and transformer means with secondariesconnected in series relation to boost the voltage of a power circuit,and primaries connected in shunt relation located in said tank, andswitch means connected to vary the amount of boost voltage in said powercircuit located in said tank, and a reactor in said regulator tank, saidreactor permanently connected in series between said voltage regulatorand said power source whereby an excessive current in said power circuitgreatly reduces the shunt voltage across both said transformer primariesand said switch means whereby said switch means is required to switchnormal currents at normal voltage and excessive currents at acorrespondingly low voltage.

3. A voltage regulator adapted to be connected to a power circuitcomprising a plurality of relatively small transformer units disposedconsecutively in a tank and having secondaries permanently connected inseries relation with each other and arranged to be connected in serieswith said power circuit for voltage regulation of said circuit; acorresponding plurality of such switch units and a manually operatedfinger member movable along a helical path and disposed for actuatingsaid snap switch units, each of said switch units being individuallyconnected to switch the primary of a respective one of said relativelysmall transformer units into and out of shunt relation with said powercircuit, the current required to be switched by each switch unit beingsmall by reason of the number of units and inversely proportional to thenumber of units used for a definite voltage regulation on said powercircuit.

4. A voltage regulator adapted to regulate the voltage of a powercircuit comprising a plurality of transformers having secondariesconnected in series relation in said power circuit and having primariesconnected to be switched successively from a short circuited position toa shunt position across said power circuit, and a plurality of reactormeans, and a plurality of capacitor means, and switch means connected toswitch a said capacitor in shunt with a said transformer primary whensaid regulator is in boost position and to switch a said reactor inshunt with a said transformer primary when said regulator is in buckposition. v

5. A voltage regulator provided with racks, a plurality of substantiallyidentical and interchangeable voltage regulating units mounted onsaid'racks, each of said units consisting of a transformer means and aswitch connected to said transformer means and arranged to throw itsconnected transformer means into and out of regulator condition, wherebyunits may be added in sequence to increase the regulating range of saidregulator and subtracted in the reverse sequence to diminish saidregulating range, and

nected in reverse position to cause said units to buck said powercircuit. and additional transformer means permanently connected to saidpower circuit and providing a fixed voltage regulation' for combinationwith a variable output 5 of said voltage regulating units.

FRAZER. W. GAY.

